Back to EveryPatent.com
United States Patent | 5,036,696 |
Ahrens ,   et al. | August 6, 1991 |
A method for measuring fracture toughness of a brittle material is described which comprises the steps of impacting a sample of the material of preselected thickness and predetermined density and characteristic ultrasonic wave velocity C.sub.i at preselected velocity with a projectile of material having a known density and characteristic shock impedence corresponding to a predetermined characteristic ultrasonic wave velocity, determining the stress .sigma. at which the sample fractures upon impact of the projectile, and determining the fracture toughness of the sample as equal to 2.sigma.(c.sub.i t/.pi.)1/2, where t is the calculated time duration of a tensile pulse traveling the thickness of the sample.
Inventors: | Ahrens; Thomas J. (Pasadena, CA); Rubin; Allan M. (Providence, RI) |
Assignee: | The United States of America as represented by the Secretary of the Air (Washington, DC) |
Appl. No.: | 561406 |
Filed: | July 30, 1990 |
Current U.S. Class: | 73/12.11; 73/799 |
Intern'l Class: | G01N 003/08 |
Field of Search: | 73/12,799,834,821,598,597 |
4210028 | Jul., 1980 | Hildebrand. | |
4413517 | Nov., 1983 | Soden. | |
4418563 | Dec., 1983 | Kalthoff et al. | 73/12. |
4522071 | Jan., 1985 | Thompson. | |
4602511 | Jul., 1986 | Holt. |
"The Effect of Oriented Cracks on Seismic Velocities", D. L. Anderson et al, J. Geophys Res. 79:26, 4011-26 (Sep. 10, 1974). "Seismic Velocities in Dry and Saturated Cracked Solids", by R. J. O'Connell, J. Geophys Res. 79:35, 5412-26 (Dec. 10, 1974). "Dynamic Tensile Strength of Lunar Rock Types", by S. N. Cohn et al., J. Geophys Res., 86:B3, 1794-1802 (Mar. 10, 1981). "Dynamic Rock Fragmentation", by Grady et al, Chap. 10, in Fracture Mechanics of Rock, Atkinson, et al, Academic Press (1987). "Experimental Fracture Mechanics Data for Rocks and Minerals", by Atkinson et al, Chap. 11, in Fracture Mechanics of Rocks, Atkinson ed, Academic Press (1987). |